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10 March 2016

RESEARCH - Canine Genetic Study Can Help Breed Healthier Dogs & Fight Disease in People

Domestic
dogs share hundreds of diseases with humans and ground-breaking research out of
Cornell University relying on canines might lead to discoveries in fighting
disease in people.

The largest genetic study of dogs conducted by the
university, recently published in the journal Nature Communications, saw the
genetic analysis of 4,200 dogs.

And the findings are a coup considered it could offer
a viable lead to help link genetic markers of disease with the responsible
gene.

“The more we know about the genetic basis of diseases,
the better we are at keeping pure-bred dog populations genetically healthy,”
says Adam Boyko, assistant professor of biomedical sciences at Cornell’s
College of Veterinary Medicine and the paper’s senior author.

The study investigated 180,000 genetic markers, DNA
sequences with a known physical location on a chromosome – ultimately offering
“a big step toward efficiently mapping genes responsible for complex disease in
dogs, most of which are very similar in humans, thereby accelerating our
understanding of human genetic diseases.”

Researchers say that by identifying important genes
and proteins in dogs for diseases and traits, it may be possible to then test
those homologous genes in humans.

In the study, samples were taken from more than 150
purebreds, 170 mixed-breed dogs and 350 free-ranging village dogs from the
Cornell Veterinary Biobank with the work taking place over several years.

From hip dysplasia to lymphoma, dogs share more than
350 diseases with humans and similar pathways and genes associated – making
mutts increasingly popular as model subjects for studying human disease.

As well genetics in dogs are far more simple than in
humans making relying on them as research tools a “useful and underused way to
understand genetic diseases from a human perspective,” Boyko says.

Existing research has made links between standard
poodles and squamous cell carcinoma, German shepherds at atopic dermatitis and
canine compulsive disorder in Dobermans, the study cites, while stating
“domestic dogs” are “excellent animal models for human disease.”

In the Cornell study, for instance, hundreds of genes
contribute to body size in humans while the research proved much easier with
canine subjects.

“We found 17 genes for body size in dogs, and by looking
at those genes we can predict a dog's size with 90 percent accuracy,” Boyko
says.

For complex diseases, researchers identified areas on
the genome associated with elbow dysplasia, hip dysplasia, lymphoma, mast cell
tumour, granulomatous colitis and idiopathic epilepsy, which is often described
as epilepsy without cause and often used to describe genetic epilepsy.

In addition to body size, researchers also succeeded
in identifying genes which influence traits like fur length and shedding.

Human disease-mapping studies generally include
genotyping tens of thousands of individuals and looking at 1 million markers
across the genome.

In this study, Boyko says, researchers conducted
simulations to show that “in dogs, we expect to be able to identify genetic risk
factors for most major diseases with 1000 individual dogs and 1000 controls.”

The study was funded by Zoetis Animal Health, the
Cornell University Center for Advanced Technology in Life Science Enterprise,
the National Geographic Society, National Institutes of Health, The American Kennel Club and the Cornell University College of Veterinary Medicine.

By Nadia Moharib

Nadia Moharib is an animal lover who has adopted
everything from birds to hamsters, salamanders, rabbits, fish and felines. She
has written about all-things-pets for years and was a long-time editor of a pet
magazine in a daily newspaper which featured a Q & A column, Ask Whit,
penned by her pooch (ghost written, of course.) The serial dog owner lives in
Calgary, Alberta and most days can be found at a dog park picking up after her
rescue pooch, Scoots.